The Martingale, or doubling up, is the best-known negative progression in gambling: you double your stake after every loss and go back to your base stake after any win. It dates from the 18th century and is, by most accounts, named after a gambling-house owner of that era. Like the D’Alembert system, it raises stakes as you lose, but far more steeply.
It is simple to follow. With a $5 base stake, a loss means the next bet is $10, then $20, then $40. A win at any point recovers all earlier losses plus a $5 profit, and the next bet returns to $5. The catch is how fast stakes grow: after seven losses in a row, the eighth bet is $640. Every table has a maximum bet and every bankroll runs out, so a long losing streak eventually stops the progression and turns many small wins into one large loss. The mirror-image approach, raising the stake after wins instead of losses, is the basis of the Paroli system.
Limits do the work
The gap between a table’s minimum and maximum bet caps how many doublings are possible. Displaying both clearly helps players understand the risk before they start. See betting limits.